Staphylococcus Classification • Family Micrococcaceae • Genus Micrococcus and Staphylococcus • Species more than 20 specie s S. aureus S. saprophyticus S.
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Transcript Staphylococcus Classification • Family Micrococcaceae • Genus Micrococcus and Staphylococcus • Species more than 20 specie s S. aureus S. saprophyticus S.
Staphylococcus
Classification
• Family
Micrococcaceae
• Genus
Micrococcus and Staphylococcus
• Species
more
than 20
specie
s
S. aureus
S. saprophyticus
S. epidermidis
M. luteus
Gram-Positive Cocci
FAMILY Streptococcaceae (catalase negative)
Group A: -hemolytic Streptococcus pyogenes
Group B: -hemolytic (occasionally or ) S. agalactiae
Group C: -hemolytic ( or ) S. anginosus, S. equismilis
Group D: or hemolytic () S. bovis
Group F: -hemolytic S. anginosus
Group G: -hemolytic S. anginosus
Viridans streptococci: (no group specific CHO)
or hemolytic S. mutans and
S. salivarius, S. sanguis, S. mitis and S. milleri groups
Streptococcus pneumoniae (no group CHO)(-hemolytic)
Enterococcus (Group D CHO) hemolytic ( or )
Enterococcus faecalis, E. faecium
FAMILY Micrococcaceae (catalase positive)
Coagulase-positive Staphylococcus aureus
Coag.-neg. Staphylococcus epidermidis, S. saprophyticus
Morphology
Morphology
Staph vs. Strep
Gram-positive cocci
in clusters
Staphylococcus
Streptococcus
Staphylococcus
See Overheads
~~~~~~~~~~
TSS
Foodborne Intoxication
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MICROBIAL
PATHOGEN
Staphylococcus aureus
Staphylococcus spp.
Group A Streptococcus
Streptococcus pneumoniae
Escherichia coli
Other Enterobacteriaceae
Neisseria gonorrhoeae
Treponema pallidum
Chlamydia spp.
Mycoplasma pneumoniae
Vibrio cholerae
ADHESIN
RECEPTOR
Lipoteichoic acid
Unknown
Slime layer
Unknown
LTA-M protein complex Fibronectin
Protein
Type 1 fimbriae
CFA 1 fimbriae
P fimbriae
Type 1 fimbriae
Fimbriae
P1, P2, P3
Cell surface lectin
Protein P1
Type 4 pili
N-acetylhexosamine-gal
D-Mannose
GM ganglioside
P blood grp glycolipid
D-Mannose
GD1 ganglioside
Fibronectin
N-acetylglucosamine
Sialic acid
Fucose and mannose
Cell-Associated Virulence Factors
• Capsule or slime layer (glycocalyx)
• Peptidoglycan (PG)
• Teichoic acid is covalently linked to PG
and is species specific:
S. aureus
S. epidermidis
ribitol teichoic acid
(polysaccharide A)
glycerol teichoic acid
(polysaccharide B)
• Protein A is covalently linked to PG
• Clumping factor (bound coagulase)
Virulence Factors
Extracellular Enzymes
• Coagulases (bound or free)
Antigenic
• Hyaluronidase
“spreading factor” of S. aureus
• Nuclease
Cleaves DNA and RNA in S. aureus
• Protease
Staphylokinase (fibrinolysin)
• Lipases
• Esterases
Virulence Factors: Exotoxins
• Cytolytic (cytotoxins; cytolysins)
Alpha toxin - hemolysin
• Reacts with RBCs
Beta toxin
• Sphingomyelinase
Gamma toxin
• Hemolytic activity
Delta toxin
• Cytopathic for:
–
–
–
–
–
RBCs
Macrophages
Lymphocytes
Neutrophils
Platelets
• Enterotoxic activity
Leukocidin
Virulence Factors: Exotoxins
• Enterotoxin
• Exfoliative toxin (epidermolytic toxin)
• Pyrogenic exotoxins
Pathogenesis
• Pass skin – first line of defense
Benign infection
• Phagocytosis
• Antibody
• Inflammatory response
Chronic infections
• Delayed hypersensitivity
Clinical Manifestations/Disease
• SKIN
folliculitis
boils (furuncles)
carbuncles
impetigo (bullous & pustular)
scalded skin syndrome
•Neonates and children under 4 years
Clinical Manifestations/Disease
• Other infections
Primary staphylococcal pneumonia
Food poisoning vs. foodborne disease
Toxic shock syndrome
Metastatic Infections
•Bacteremia
•Osteomyelitis
disease of growing bone
• Pulmonary and cardiovascular
infection
Coagulase-Negative Staphylococci
• Staphylococcus epidermidis
• S. saprophyticus
Staphylococcal Lab ID & Diagnostic Tests
• Microscopic
• Lab isolation
• Coagulase positive
S. aureus
Mannitol Salts Agar
(MSA)
Staphylococcus aureus
Differential Characteristics
Catalase
2H2O2 O2 + 2H2O
Streptococci vs. Staphylococci
Catalase POS
Staphylococcus
Catalase NEG
Differential
Characteristics
S. aureus
Coagulase
Fibrinogen Fibrin
Staphylococcus
aureus
Coagulase POS
Coagulase NEG
Treatment
• Drain infected area
• Deep/metastatic infections
semi-synthetic penicllins
cephalosporins
erythromycin
clindamycin
• Endocarditis
semi-synthetic penicillin + an aminoglycoside
Prevention
• Carrier status prevents complete control
• Proper hygiene, segregation of carrier
from highly susceptible individuals
• Good aseptic techniques when
handling surgical instruments
• Control of nosocomial infections
REVIEW
Gram-Positive Cocci
FAMILY Streptococcaceae (catalase negative)
Group A: -hemolytic Streptococcus pyogenes
Group B: -hemolytic (occasionally or ) S. agalactiae
Group C: -hemolytic ( or ) S. anginosus, S. equismilis
Group D: or hemolytic () S. bovis
Group F: -hemolytic S. anginosus
Group G: -hemolytic S. anginosus
Viridans streptococci: (no group specific CHO)
or hemolytic S. mutans and
S. salivarius, S. sanguis, S. mitis and S. milleri groups
Streptococcus pneumoniae (no group CHO)(-hemolytic)
Enterococcus (Group D CHO) hemolytic ( or )
Enterococcus faecalis, E. faecium
FAMILY Micrococcaceae (catalase positive)
Coagulase-positive Staphylococcus aureus
Coag.-neg. Staphylococcus epidermidis, S. saprophyticus
REVIEW
Which features are only found in S. aureus?
S. aureus
S. epidermidis
REVIEW
REVIEW
REVIEW
REVIEW
REVIEW
REVIEW